The Tennessee Office of the Attorney General has released an opinion finding that a state law requiring products labeled as “Tennessee Whiskey” or similar designations to be filtered through charcoal unconstitutionally exempts Prichard’s Distillery because the statute includes a grandfather clause created to apply only to the distillery.

The 2013 law codified the “Lincoln County Process” of making whiskey, which requires that the product is (i) manufactured in Tennessee; (ii) composed of 51 percent corn; (iii) distilled to no more than 80 percent alcohol by volume; (iv) aged in new, charred oak barrels in-state; (v) filtered through maple charcoal before aging; (vi) placed in the aging barrels at no more than 62.5 percent alcohol by volume; and (vii) bottled at no less than 40 percent alcohol by volume. If a product does not fulfill each requirement, it cannot be advertised, labeled or referred to as “Tennessee Whiskey” or “Tennessee Sour Mash Whiskey” (or the alternative spelling of “whisky”).

The law was passed to differentiate Tennessee whiskey from bourbon; most of the requirements reflect federal standards of identity for bourbon, but charcoal filtering is unique to the Tennessee statute. Prichard’s Distillery owner Phil Prichard says that requirement “was designed to benefit one company”—Jack Daniel’s—but Tennessee Attorney General Herbert Slatery argues that Prichard’s Distillery is the company receiving special treatment under the statute. The provision exempts from the law distilleries “located in a county that authorized the manufacturing process by referendum” in 1979 and that were “first licensed by the state alcoholic beverage commission” in 2000—specificity that only applies to Prichard’s Distillery. “There is no discernable reason to distinguish one distillery from other existing distilleries on this basis,” the opinion states, “especially since the exemption at issue is purportedly one that distinguishes Tennessee Whiskey from bourbon.” Accordingly, the opinion finds that the exemption violates the federal and Tennessee constitutions. See The New York Times, March 19, 2015.